Pleomorphic undifferentiated sarcoma
Jump to navigation
Jump to search
Pleomorphic undifferentiated sarcoma, abbreviated PUS, is an undifferentiated malignant soft tissue lesion.
| Pleomorphic undifferentiated sarcoma | |
|---|---|
| Diagnosis in short | |
 Pleomorphic undifferentiated sarcoma. H&E stain. | |
|
| |
| Synonyms | undifferentiated pleomorphic sarcoma (UPS), malignant fibrous histiocytoma (MFH) |
|
| |
| LM | storiform pattern (AKA patternless pattern), marked nuclear pleomorphism, mitoses, necrosis (common), mix of spindle cells and epithelioid cells, deep to skin |
| LM DDx | atypical fibroxanthoma (superficial), dedifferentiated liposarcoma, leiomyosarcoma,metaplastic carcinoma, malignant melanoma, rhabdomyosarcoma, synovial sarcoma,Undifferentiated endometrial sarcoma, others |
| Site | deep soft tissue - trunk and extremities |
|
| |
| Prevalence | uncommon overall |
| Prognosis | poor |
| Treatment | surgery if feasible |
It is also known as undifferentiated pleomorphic sarcoma (abbreviated UPS). Previously, it was known as malignant fibrous histiocytoma, commonly abbreviated MFH.[1]
General
- Common sarcoma.
- Usually deep tissue of the trunk and extremities.
- A diagnosis of exclusion[2] / wastebasket for unclassifiable high grade sarcomas.
Microscopic
Features:[3]
- Storiform pattern (AKA patternless pattern) - key feature.
- Marked nuclear pleomorphism key feature.
- Variation is nuclear size, nuclear shape and nuclear staining (esp. hyperchromasia).
- Mitoses - abundant; atypical mitoses common.
- Necrosis (common).
- Mix of spindle cells and epithelioid cells.
- Deep to skin - important.
Other findings:
- +/-Giant cells (see subclassification).
- +/-Inflammation (see subclassification).
- Neutrophils.
- Eosinophils.
Notes:
- Superficial lesions with the morphology of PUS are called by some atypical fibroxanthomas (AFXs).
DDx:
- Atypical fibroxanthoma (AFX) - superficial skin.
- Dedifferentiated liposarcoma.
- Leiomyosarcoma.
- Metaplastic carcinoma.
- Malignant melanoma.
- Rhabdomyosarcoma.
- Synovial sarcoma.
- Undifferentiated endometrial sarcoma - uterus.
- Others.
Images
PUS - high mag. (WC/Nephron)
PUS - intermed. mag. (WC/Nephron)
Subclassification
Pleomorphic sarcoma (PS) is subclassified the following way:[4]
- PS with giant cells.
- PS with inflammation.
- PUS (not otherwise specified) - wastebasket diagnosis; if neither of the above two apply.
IHC
Exclusionary stains - should be negative:
- AE1/AE3.
- p63.
- Myogenin.
- S-100.
- HMB-45.
Usually negative, may be positive:[5]
- Desmin.
- SMA.
Commonly positive:
- CD68.[5]
- Vimentin.
See also
References
- ↑ URL: http://sarcomahelp.org/learning_center/mfh.html. Accessed on: 8 April 2011.
- ↑ Matushansky I, Charytonowicz E, Mills J, Siddiqi S, Hricik T, Cordon-Cardo C (August 2009). "MFH classification: differentiating undifferentiated pleomorphic sarcoma in the 21st Century". Expert Rev Anticancer Ther 9 (8): 1135–44. doi:10.1586/era.09.76. PMC 3000413. PMID 19671033. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3000413/.
- ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 613. ISBN 978-0781765275.
- ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 613-4. ISBN 978-0781765275.
- ↑ 5.0 5.1 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 613. ISBN 978-0781765275.